Aircraft secondary power has traditionally been extracted through pneumatic power (engine bleed air), electrical power (shaft driven generators), and hydraulic power (via shaft driven pumps, augmented by pneumatic driven pumps). Pneumatic power has traditionally been used for functions such as hydraulics power augmentation, Environmental Control Systems (ECS), ice protection, nitrogen generation (fuel inerting), and engine starting. Electrical power has traditionally been used for ECS, cabin services, avionics, galley refrigeration, and others miscellaneous functions. In those traditional architectures, the pneumatic and electrical power have been isolated and managed separately. In either case, the designers recognize that the pneumatic and electrical power sources have limits and that the extraction of power from these sources must be managed to ensure critical limits are not exceeded.
Traditionally, electrical load management has been accomplished in a mostly discrete (on/off) manner. Most loads are either allowed to draw power or not. For example, load shedding of specific power users in the event of an overload, and sequenced restoration of electrical power users after the overload condition has ceased.
In some cases, electrical load management has utilized partial load reduction for some power users. However, these reductions were still discrete steps.
Pneumatic load management has also used similar techniques such as load management via discrete shedding of associated power users (pneumatic load either being completely off or on) or discrete load reduction (loads being set to predetermined states that reduce power extraction). However, pneumatic power systems also provide more dynamic, real time load management capabilities. The bleed extraction ports naturally limit the total flow, therefore protecting the engine from excess power extraction under most operating cases (in some cases discrete load management must be employed to stay below engine limits). Additionally, when the bleed source is at or near its extraction limits, a pneumatic power system will naturally share power between users. In this case, as one power user draws more flow, another users flow will naturally droop. These sorts of natural power sharing do not occur in the electrical power realm.
A new secondary power extraction architecture has been developed for the 787 aircraft. This secondary power extraction architecture does not use pneumatic power (bleed air). In this case, the traditional bleed air users use electric power. An outcome of this architecture is a dramatic increase in the electrical power usage levels and a significant increase in the number of electrical power users to integrate and manage via electrical power load management. Although many of the traditional electrical load management techniques discussed above can still be effectively used in this case, they did not offer analogous functionality and flexibility that the dynamic, real time load management capabilities of pneumatic systems offered.
A method and/or system for dynamic management of electrical power loads is needed in order to decrease one or more problems, such as the potential for overload conditions, of one or more of the existing systems and/or methods in aircraft, non-aircraft, vehicles, structures, and/or devices.